If users are limited they are only allowed to authenticate via their ssh
private-public key-pair, which the configuration holds for each accepted
user accordingly.
Configured default arguments are replaced with provided arguments
through the `ssh` command. Without any arguments the default arguments
are used instead.
Logging will be done through `zlog` dependency for *zig* based
applications. `zlog` shall be configured such that it should not log to
*stderr* and should use the "log" file instead. This way the log file is
both used by `serve` and by the running application. Logging could also
happen in a different file and is independent of the logging of `serve`,
however for now I want the logging to also happen in the same file.
